More L4D. Louis chibi by Wibblethefish on Deviantart. (I added the lipstick mark.)

Don't play or still don't get it? Louis is the optimistic survivor, he gets excited about things. While the others find pills and say "Found pills" Louis exclaims "Grabbin' Peeeels!" Although, from my experience, Bill is the one with the secret pill stach, everyone has latched onto Louis and his peels. Hence the "addiction" pun.